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Showing papers on "Power system simulation published in 1988"


Journal ArticleDOI
TL;DR: In this article, a method for online transient stability assessment of large power systems is proposed, which consists of replacing the multimachine system by a two-machine dynamic equivalent, further amenable to a one-machine-infinite-bus system.
Abstract: A method for online transient stability assessment of large power systems is proposed. It consists of: replacing the multimachine system by a two-machine dynamic equivalent, further amenable to a one-machine-infinite-bus system; reducing the stability problem to a sole algebraic equation, devised from the equal area criterion, or equivalently from the Lyapunov direct criterion; and using this equation to derive one-shot stability analysis strategies. A technique for system admittance matrix reduction is developed that proves efficient, especially for large systems and multiple-contingency evaluation. The method's main appeal is rapidity: it is about one order of magnitude faster than the most efficient direct criterion. Other attractive features are flexibility and ability to encompass various simulation conditions. Extensions to online sensitivity analysis and control are suggested. >

257 citations


Journal ArticleDOI
TL;DR: In this article, an enhanced dynamic programming (DP) approach which saves predecessor options was developed and implemented in an online energy management system, which not only supports realistic modelling of unit start-up ramps, but also involves the analysis of solution paths that may have been eliminated under traditional methods, thereby making better solutions possible.
Abstract: To investigate modeling problems with predefined unit hourly start-up ramps, the authors look at the method by which dynamic programming (DP) considers and reject combinations. An enhanced DP approach which saves predecessor options was developed and implemented in an online energy-management system. The method not only supports realistic modelling of unit start-up ramps, but it also involves the analysis of solution paths that may have been eliminated under traditional methods, thereby making better solutions possible. Sample results are given to demonstrate the benefits of the proposed algorithm. >

225 citations


Journal ArticleDOI
TL;DR: A rule-based system for screening the consequences of single outages was developed which can be extended to deal with multiple outages and shows that such systems can be very effective in focusing attention on a much-reduced number of the more critical contingencies.
Abstract: The power system security assessment problem is considered. The objective is to investigate the extent to which a computer program with knowledge and inference capabilities can assist a human operator in this task. A rule-based system for screening the consequences of single outages was developed which can be extended to deal with multiple outages. The rules are independent of the size of the power system and derive partly from human operator expertise and partly from simulation models. Results show that such systems can be very effective in focusing attention on a much-reduced number of the more critical contingencies. The expert system was demonstrated using a power system model of moderate size (25 buses, 35 lines). This approach is cost effective and can be applied to online operation. >

79 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a method for problem solving the short-term generation scheduling problem in a small autonomous system with both conventional and unconventional energy sources and a storage battery, which consists of diesel generators, wind turbine generators, and photovoltaic panels.
Abstract: The authors present a method for problem solving the short-term generation-scheduling problem in a small autonomous system with both conventional and unconventional energy sources and a storage battery. The system generation consists of diesel generators, wind turbine generators, and photovoltaic panels. This is the generation mix of the power system of the Greek island of Kythons, and may be applied to other Greek islands. A dynamic programming algorithm together with a standard unit commitment, is used to determine the optimal short-term scheduling, which minimizes the fuel consumption for a certain scheduling horizon, e.g., for the next 24 h. >

77 citations


Journal ArticleDOI
TL;DR: In this article, an integration method which can be numerically tuned to suit the system of equations is developed and is shown to be superior to the trapezoidal rule when very long time steps are used.
Abstract: Accurate simulation of power-systems dynamics over an extended time period results in a model that is relatively stiff; the solution of such models requires a numerical integration method that is not only fast and accurate, but also capable of using long time steps. An integration method which can be numerically tuned to suit the system of equations is developed and is shown to be superior to the trapezoidal rule when very long time steps are used. While the fixed-tuning methods are easy to implement, they are not recommended since they resulted in no significant improvements. Adaptively tuned techniques performed better and some worthwhile gains were obtained with long time steps. >

19 citations


Journal ArticleDOI
TL;DR: In this paper, a model for simulating the plant dynamics of light-water-reactor (PWR) and BWR plants under both small and large power system disturbances is presented.
Abstract: Models have been developed for simulating the plant dynamics of light-water-reactor (PWR and BWR) plants under both small and large power system disturbances. The model permits precise and effective analysis of the dynamics of the nuclear plant response to power system faults by combining the plant model with the conventional power system dynamics simulation program. The modeling of the nuclear plant is described, and the application of the model to power system dynamics simulation is outlined. >

14 citations


Journal ArticleDOI
TL;DR: In this article, a general and efficient method for transient simulation of HVDC converters is presented, which utilizes a novel algorithm that is based on network topological concepts and provides an efficient solution to the problem of modeling the inherently nonlinear characteristics and time-varying topology of static power converters caused by the switching action of the thyristor valves.
Abstract: A general and efficient method is presented for transient simulation of HVDC converters. The method utilizes a novel algorithm that is based on network topological concepts and provides an efficient solution to the problem of modeling the inherently nonlinear characteristics and time-varying topology of static power converters caused by the switching action of the thyristor valves. The application of the algorithm to a six-pulse converter unit results in an extremely flexible and efficient model that can be easily interfaced to both the AC and DC sides of an integrated AC/DC system. >

12 citations


Journal ArticleDOI
TL;DR: A novel generator module for a real-time power system simulator was developed, where a multiprocessor and an analog three-phase sinusoidal oscillator are used to simulate the generator behavior.
Abstract: A novel generator module for a real-time power system simulator was developed. In this simulation module, a multiprocessor and an analog three-phase sinusoidal oscillator are used to simulate the generator behavior. A multiprocessor consisting of four microprocessors solves the differential equations in parallel to lessen the simulation time interval, and uses floating-point arithmetic to obtain high accuracy of the simulations. Any type of generator can be simulated using the developed module, since the parameters of the generator are easily modified by simply changing the data of the multiprocessor program. The initial condition of the power system simulator is automatically set up by a host computer. The accuracy of the generator module is validated by comparisons with the offline simulation program EMTP (Electromagnetic Transients Program). >

11 citations


Journal ArticleDOI
01 Jul 1988
TL;DR: The results illustrate that the proposed decomposition technique results in a significant saving in simulation elapsed time, and can consequently be applied to the real-time simulation of large power systems, using relatively inexpensive microprocessor-based hardware.
Abstract: The paper considers real-time simulation over the operational timescales in an electrical power system and presents a mathematical technique for the decomposition of a set of nonlinear algebraic and differential equations, which result from the corresponding dynamic model. It is shown that the resulting algorithm is suitable for implementation on parallel processors with a 32-bit word capability. The results illustrate that the proposed decomposition technique results in a significant saving in simulation elapsed time, and can consequently be applied to the real-time simulation of large power systems, using relatively inexpensive microprocessor-based hardware.

7 citations


Journal ArticleDOI
TL;DR: In this article, the authors present selected results of recent field tests carried out on the 220 kV, 660 km radial static VAr compensated Muja-Kalgoorlie transmission system in Western Australia.
Abstract: The authors present selected results of recent field tests carried out on the 220 kV, 660 km radial static VAr (volt-ampere reactive) compensated Muja-Kalgoorlie transmission system in Western Australia. Measured results on network harmonics, SVC (static VAr compensator) losses and the responses of the power system under small and large-disturbance conditions are discussed. The recorded data have also been used to validate and improve the computer models used in simulation studies. >

6 citations


Proceedings ArticleDOI
26 Jan 1988
TL;DR: A simulation program (SIMULAV) is presented that is capable of modeling large-scale reliability systems and its uses the minimal cut-sets to determine system failure.
Abstract: A simulation program (SIMULAV) is presented that is capable of modeling large-scale reliability systems. The program can model the effect of such logistics characteristics as inventory, transportation, and facilities on the reliability and availability of the system. The program is written in Pascal and it consists of three main elements: a process-oriented simulation language, a minimal cut-sets algorithm, and a simulation model to estimate the availability of a complex system. The model is implemented using the process-oriented simulation language and its uses the minimal cut-sets to determine system failure. It assumes that the system can be represented by a reliability block diagram. Examples are modeled to show how SIMULAV can be used to assess the effect of some logistic parameters on the availability of the system. >

Journal ArticleDOI
TL;DR: The authors describe the use of the SPICE 3 programming language for power system fault analysis and its ability to model the operations of a switch makes it quite suitable for transient analysis of electrical circuits.
Abstract: The authors describe the use of the SPICE 3 programming language for power system fault analysis. SPICE 3 is a general-purpose simulation program for analysis of DC or AC electrical circuits. One of the additional features of this language as compared to its previous version is its ability to model the operations of a switch. It is concluded that this makes SPICE 3 quite suitable for transient analysis of electrical circuits. The versatility and capability of this language are demonstrated by two simple example problems. >

Proceedings ArticleDOI
Satoshi Matsuda, H. Ogi, K. Nishimura1, Y. Okataku1, S. Tamura1 
25 May 1988
TL;DR: In this paper, a case study of the application of a distributed control scheme to power system control is presented, where the combined injection of VAr-compensating devices controlled by distributed expert systems is proposed as a measure to maintain voltage stability in heavy loading conditions of a power system.
Abstract: Voltage control by distributed expert systems has been investigated as a case study of the application of a distributed control scheme to power system control. The combined injection of VAr-compensating devices controlled by distributed expert systems has been proposed as a measure to maintain voltage stability in heavy loading conditions of a power system. A simulation study has been carried out using five workstations which represent a power system and four VAr-compensating devices. The results demonstrate the effectiveness of the proposed system for voltage recovery. >

Book ChapterDOI
01 Jan 1988
TL;DR: This chapter deals with an efficient dynamic optimization technique for minimizing the cost of production over a specified time horizon and its applications to the unit commitment and hydrothermal coordination problems.
Abstract: In the optimal power flow (OPF) problem the optimization process is static. The cost of production is an instantaneous function of demands. Since the load varies on a continuous basis with fairly predictable patterns, optimization over certain time ranges becomes necessary for some time-dependent functions. For the purposes of this chapter the focus will be on the unit commitment (UC) and hydrothermal coordination (HTC) problems. In both of these one is concerned with minimizing the cost of production over a specified time horizon (e.g., several days). This requires three basic tools: (a) an efficient dynamic optimization technique, (b) a good load forecast and (c) the ability to adjust for forecasting errors. In this chapter one deals with the first tool in its applications to the UC and HTC problems. Forecasting is dealt with later in this book. Adjustments for forecasting errors belongs to the domain of stochastic (or adaptic) control and is beyond the scope of this book.

Journal ArticleDOI
TL;DR: The ability to do calculations has surpassed the ability to manage the data, and the task now is to update data systems to work with the more extensive data needed by current programs and to move away from the use of derived parameter values toward theUse of original data.
Abstract: The author describes power-system computer applications from the viewpoint of network-related simulation He examines the development of techniques for power system network analysis. He contends that the ability to do calculations has surpassed the ability to manage the data, and that the task now is update data systems to work with the more extensive data needed by current programs and to move away from the use of derived parameter values toward the use of original data. He bases his argument on the idea that many different analytical functions will make use of the databases and that each will use the original data in mathematical models that are appropriate for itself. >

Proceedings ArticleDOI
01 May 1988
TL;DR: The development and features of an expert system package to assist the supervisor in the control center at a distribution or transmission level is described along with criteria for its application.
Abstract: The development and features of an expert system package to assist the supervisor in the control center at a distribution or transmission level is described along with criteria for its application This microcomputer package is intended for use in a power system configuration with distributed control centers The expert system analyzes the electrical system's voltage and power flow parameters and helps the operator to organize strategies and plans of actions when the parameters fall outside of specified limits With a simulator, the package can also be used for training personnel >

Proceedings ArticleDOI
15 Jun 1988
TL;DR: In this paper, the authors present an overview of the existing parallel architecture types, followed by a brief survey of the algorithms which have been developed for power system simulation utilizing various parallel processors, and their main contribution in the final section by presenting recent efforts in the application of waveform relaxation methods to power systems.
Abstract: In this paper the authors present an overview of the existing parallel architecture types, followed by a brief survey of the algorithms which have been developed for power system simulation utilizing various parallel processors. The authors present their main contribution in the final section by presenting recent efforts in the application of waveform relaxation methods to power systems. The authors correlate the physical properties of the power system to the rate of convergence of the numerical waveform iterations.

Proceedings ArticleDOI
07 Jun 1988
TL;DR: A modelling approach for the detailed dynamic simulation of multiterminal HVDC systems embedded in a conventional AC network is presented that utilizes a decomposition technique to construct separately the state equations of properly defined subsystems, which are linked using automatically created algebraic equations of the state variables.
Abstract: A modelling approach for the detailed dynamic simulation of multiterminal HVDC systems embedded in a conventional AC network is presented. This approach utilizes a decomposition technique to construct separately the state equations of properly defined subsystems, which are linked using automatically created algebraic equations of the state variables. Also, a novel converter model suitable for the efficient representation of multiterminal HVDC systems is used. Any control system applied to the converters or the AC machines can be easily incorporated using the proposed modelling technique. The effectiveness of the solution algorithm is demonstrated on a test system including a three-terminal DC system. >